The present invention relates to an apparatus for detecting abnormality of a tension sensor of a magnetic recording apparatus suitable for use in a data recorder, for example.
In a magnetic recording apparatus such as a data recorder or the like, control of tape tension for controlling a reel motor of a supply-side reel is performed on the basis of a tape tension detected by a tension sensor disposed at a tape traveling path so that a tape can be traveled with a predetermined tension.
As a method of the tension control, there is a method of open-loop control in which a predetermined current is supplied to the supply-side reel motor to generate a necessary torque and a method of feed-back control in which a value of the tape tension detected by the tension sensor is fed back to control the supply-side reel motor.
In a tape traveling mode, since a tape is required to slide on and brought in contact with a part of the outer peripheral end surface of a drum to enable magnetic recording, a precise value of the tape tension needs to be maintained. For these reasons, a feed-back control which allows fine control is frequently adopted.
However, a magnetic recording apparatus performing the above-mentioned feed-back control of the tape tension encounters by such a disadvantage that if the tension sensor becomes out of order and malfunctions, then not only is the correct tape tension is prevented from being maintained but also the tape is prevented from being properly sliding on the outer peripheral end surface of the drum, with the result that correct recording and reproduction is prevented and the tape is apt to be damaged.